Technical Research Of Dental Endoscope Imaging System Based On Wavefront Coding Method

The modern dental endoscope has two different types, photographic type and microscopic type. Compared with microscopic dental endoscope, the photographic dental endoscope performs better in the depth of field and the field of view. However, the most significant defect of photographic dental endoscope is the poor ability of resolution. Meanwhile, the microscopic dental endoscope has better ability of resolution. In order to solve the contradiction between the depth of field and the resolution in endoscopic imaging system, a new integrated optical imaging technology which is called as wavefront coding , is introduced in this dissertation. The main contents of this dissertation are as follows:According to ral diagnostic requirements, a wavefront coding dental endoscope design is proposed, which can extend the depth of field and guarantee the field of view and resolution. Meanwhile ,the design can effectively solve contradiction between the depth of field and the resolution.A phase mask optimized method based on the standardized correlation coefficient is introduced and the wavefront coding dental endoscope’s defocus invariance curve is accomplished. The range of phase plate normalized parameter is obtained. The specific phase mask normalized parameter is obtained by ZEMAX. Meanwhile the design and the evaluation of wavefront coding dental endoscope is accomplished.A im age acquisition s ystem design is prop osed, which accom plish the im age acquisition, transmission and display.The wavefront coding image degradation function estimation module is improved. The resolution board and oral lesion coded image is restored by wiener filtering algorithm based the degradation.